1. Field of the Invention
The present invention relates to gaseous recovery systems for storage tanks, and more particularly to systems for recovering gases which are associated with storage tanks which are improperly operating, e.g., gases which are directly discharged through a safety valve when they are under an overpressure or gases created when liquids leak outwardly therefrom.
2. The Prior Art
Storage tanks used to contain volatile liquids and gases must always be constructed to include safety devices, such as discharge lines with safety valves, so that if and when liquids leak out (and vaporize) or if overpressures occur in the tanks, e.g., due to the contained liquids and/or gases heating up to unexpectedly high temperatures, the escaping gases can be blown off. However, if the escaping gases are offensive to smell, toxic or ecologically harmful, or if they are valuable (e.g., noble gases), they cannot be simply vented to the atmosphere, but must be recovered and/or suitably disposed of.
One known way to deal with this problem is to convey the discharged gases from such storage tanks to respective collecting tanks. However, it can never be predicted in advance how long a safety valve will be open in any given system and thus how much gas will be discharged. Thus, the utilized storage tanks must be very large, which is not economical. In addition, it cannot be guaranteed that even a very large collecting tank will be sufficient to store the discharged gases in all situations.
Another procedure is to convey the discharged gases to a burn-off tube where they are burned off. However, this procedure has disadvantages too. For example, when large quantities of gases are burned, dangerously large flames can result. In addition, the gases themselves are consumed, which can be quite uneconomical.
It is thus an object of the present invention to provide a system for recovering the gases from a storage tank, i.e., either the gases discharged directly therefrom or the gases generated from leaking liquids, which system is technically simple and economical, yet will provide a high degree of safety.